Similar cortical but not subcortical gray matter abnormalities in women with posttraumatic stress disorder with versus without dissociative identity disorder

Abstract

Neuroanatomical evidence on the relationship between posttraumatic stress disorder (PTSD) and dissociative disorders is still lacking. We acquired brain structural magnetic resonance imaging (MRI) scans from 17 patients with dissociative identity disorder (DID) and co-morbid PTSD (DID-PTSD) and 16 patients with PTSD but without DID (PTSD-only), and 32 healthy controls (HC), and compared their whole-brain cortical and subcortical gray matter (GM) morphological measurements. Associations between GM measurements and severity of dissociative and depersonalization/derealization symptoms or lifetime traumatizing events were evaluated in the patient groups. DID-PTSD and PTSD-only patients, compared with HC, had similarly smaller cortical GM volumes of the whole brain and of frontal, temporal and insular cortices. DID-PTSD patients additionally showed smaller hippocampal and larger pallidum volumes relative to HC, and larger putamen and pallidum volumes relative to PTSD-only. Severity of lifetime traumatizing events and volume of the hippocampus were negatively correlated. Severity of dissociative and depersonalization/derealization symptoms correlated positively with volume of the putamen and pallidum, and negatively with volume of the inferior parietal cortex. Shared abnormal brain structures in DID-PTSD and PTSD-only, small hippocampal volume in DID-PTSD, more severe lifetime traumatizing events in DID-PTSD compared with PTSD-only, and negative correlations between lifetime traumatizing events and hippocampal volume suggest a trauma-related etiology for DID. Our results provide neurobiological evidence for the side-by-side nosological classification of PTSD and DID in the DSM-5.

Structural brain aberrations associated with the dissociative subtype of post‐traumatic stress disorder

“…In the light of these findings, recent therapeutic advances combining a structured emotion regulation training with exposure treatment (58,59) would seem to be particularly suited for patients belonging to dissociative subtype of PTSD. Our findings also suggest that the dissociative symptoms seen in PTSD (transient depersonalization/derealization) might be associated with other anatomical aberrations than those seen in chronic dissociative disorders, for which extensive subcortical volume differences have been reported (35,60).…”

“…Notably, amygdalar, hippocampal and parahippocampal volumes showed no between-group differences, even at the very lenient threshold employed for the region-of-interest analyses. This is of interest as previous studies on structural brain aberrations in patients with dissociative disorders involving identity alterations reported smaller amygdalar, hippocampal and parahippocampal brain volumes (33, 34, but also see 35).…”

Neurodevelopmental origins of abnormal cortical morphology in dissociative identity disorder

“…Previous studies examining neuroanatomical alterations in DID mostly focused on subcortical regions . However, a recent study by our group has also investigated brain abnormalities in DID on the cortical level using an exploratory approach in a set of 68 predefined cortical areas across the cortex and reported that individuals with DID have significantly reduced gray matter volume in the medial and dorsolateral prefrontal cortex, the anterior cingulate, the insular cortex, inferior parietal areas, and in several regions within the temporal lobe . A high degree of overlap was found between these neuroanatomical aberrations and dissociative personality state‐dependent brain functioning during emotion regulation, which showed predominantly activation in the parietal regions, insula and limbic‐prefrontal circuitry .…”

“…Dissociative identity disorder (DID) is considered an early‐onset and chronic interpersonal trauma‐related disorder . For early‐onset interpersonal trauma‐related disorders, it is currently unknown how early traumatization affects the development of the brain and what particular aspect of the cortical neuroanatomy is most affected.…”

“…It is thus crucial for our understanding of the effects that early‐onset and chronic interpersonal traumatization has on the brain, and which particular aspects of the cortical architecture are most vulnerable. Last, only few studies to date have investigated the relationship between dissociative symptoms and measures of structural brain morphology , and the neurobiological correlates of dissociative symptoms therefore remain poorly understood.…”